The semi-weekly fisherman & farmer. [volume] (Edenton, N.C.) 1886-1887, 1887-09-09
SCIENTIFIC AND INDUSTRIAL.

By careful experiments VI. Bloch has
determined that ii takes l. 70 OF second
longer to hear sound than to see sight,
and 1.21 of a second longer to feel touch
than to see sight.
Chemical decomposition has been pro-
duced by pressure in the experiments of
two Belgian chemists. Under pressure
of 6, 900 atmospheres, at temperature of
104 degrees, a pulveriZed acetate Of
copper and lime was slowly hquetied,
and on removal of the pressure the sur
face of the instrument in contact with
salt was found coated with copper.
The nutritive value of mushrooms has
been Investigated in Germany by c. L.
Moerner, who shows that to get an
equivalent of an average hens egg a
person must eat ten and half ounces of
Agdricus c0mpestris, or no less than four
pounds P0Lyp0rus OcinuS;; and that nine
pounds of the former variety, or sixty
seven of the latter, would be needed to
equal a pound of beef.
Cotton, according to a scientific au-
thority, is not fibre, but a plant hair.
1t holds to be spun in a thread because of
peculiar twists in each hair, shown by
the microscope, especially in polarized
light. Linen thread may be spun be-
cause the fax fbers have certain rough
ness on their surfaces which enable them
to cling together. Hence it is impossi-
BILE to make as fine linen as cotton cloth,
but it is much stronger.
Among the many masses of meteOric
iron which have been described, only
nine, according to Prof. w. f. Hidden,
have been seen to fall, the places and
Ia+o ('rootin
1851; Charlotte, Tenn, August l, 1885;
Brauman, Bohemia, July IA, 1S47;
Tabarz, Saxony, October Is, 1854; Vic
toria West, Africa, in 1862; Nejed,
Arabia, spring of 1865; Nedagolla, India,
January %, 1870; Rowton, Shropshire,
England, April 20, 1876; Mazapll,
Mexico, November q, 1885.
Electric lanterns will, it is thought,
take the place, in course of time, of the
ordinary mining safety lamps A port
able electric lamp can now be made,
possessing the following features !:
Weight, about three pounds; illuminat-
ing power, five candles size and shape,
similar to present lamps; duration of
light, ten hours; cost of repairs, charges
of battery, and materials, two cents for
ten hours; these facts showing that there
is nothing to prevent its adoption as a
substitute for the present lamps, and
even for candles in many mines where
they are still in use.
1t has been laid down by M. Chevreul
that the human eye cannot be long en-
ployed in the PERCEPTION of a given color
without tending to become insensible and
to arouse an impression similar to that
produced by the perception Of white
light. DR.. Beclard has also noticed that
when the eye is directed for time upon
colored field, the other eye being
closed, if the eye which was open be in
turn closed and the other opened
spectre of the complementary color will
be perceived; thus, if the right eye has
observed a red disk, the left being shut,
a reversal of this state of things would
result in the perception of green disk
by the freshly opened left eye. In virtue
of the same property of the eye, when
two tints are placed beside each other
the nearest edge of the one will appear
as though deprived of all the colored
rays which it may have in common with
the other. Analogous effect is produced
with grays non-colored, that is to say,
formed simply of white and black.